From a0d570170647a430022c624747dc65cd4e500ee4 Mon Sep 17 00:00:00 2001 From: Kévin Le Gouguec Date: Wed, 13 Feb 2019 14:37:39 +0100 Subject: Clarification de commentaires dans l'implémentation MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit --- src/ref/lilliput-ii.c | 14 +++++++++++++- 1 file changed, 13 insertions(+), 1 deletion(-) (limited to 'src/ref/lilliput-ii.c') diff --git a/src/ref/lilliput-ii.c b/src/ref/lilliput-ii.c index 8238b08..7c02bce 100644 --- a/src/ref/lilliput-ii.c +++ b/src/ref/lilliput-ii.c @@ -32,6 +32,8 @@ static void _init_msg_tweak(const uint8_t tag[TAG_BYTES], uint8_t tweak[TWEAK_BY * [ 1, 64]: tag[ 1.. 64] XOR block index * [ 65, t-1]: tag[65..t-1] * - bit t: 1 + * + * This function sets bits 65 to t once and for all. */ memcpy(tweak+sizeof(uint64_t), tag+sizeof(uint64_t), TAG_BYTES-sizeof(uint64_t)); @@ -40,7 +42,17 @@ static void _init_msg_tweak(const uint8_t tag[TAG_BYTES], uint8_t tweak[TWEAK_BY static void _fill_msg_tweak(const uint8_t tag[TAG_BYTES], uint64_t block_index, uint8_t tweak[TWEAK_BYTES]) { - /* Assume bits 65 to t-1 are set. */ + /* The t-bit tweak is filled as follows: + * + * - bits [ 1, t-1]: tag + block index + * [ 1, 64]: tag[ 1.. 64] XOR block index + * [ 65, t-1]: tag[65..t-1] + * - bit t: 1 + * + * This function assumes bits 65 to t have already been set, and + * only sets bits 1 to 64. + */ + for (size_t i=0; i> i*8 & 0xff; -- cgit v1.2.3